Donatello

Don is depicted to be the brains of the team, as he is the most logical, intelligent, and level headed of the three. Due to his genius, is he usually the team's strategist and engineer. He is also known for his sarcasm, negotiation tactics, and patience.

With the impossible IQ of 637, Donatello is inarguably a complete genius and is a stud at fixing/building electronics, as well as a master tactician who can plan the most dangerous attacks even in the heat of a battle. Though, he does have some brawn with his brains, as he's a master at Ninjutsu and has the main weapon of a wooden bo-staff, which he is amazing with via his intense Stickjitsu training.